DE3144884A1 - Bicycle, in particular with an electric motor - Google Patents

Abstract

The invention relates to a bicycle with a drive by means of an electric motor having the features that the electric drive and the pedal drive act on the gearing of the rear wheel hub via respectively assigned chains and chain wheels and free-wheels are assigned to the chain wheels of the two drive systems. A travel speed sensing device, in particular by means of an electronic pulse sensing device is present, the motor being switched on only when a minimum speed of the bicycle, preferably approximately one metre per second, is reached. The crossbar is designed as a tube and houses the electric motor. The suspension of the front wheel or of the front wheel fork is arranged in the steering head pipe. Magnets are arranged on the circumference of the rim of a wheel at uniform intervals and a coil or a plurality of coils is present on the side of the fork of the wheel lying opposite the magnets. <IMAGE>

Description

Bicycle, especially with an electric motor.

The invention relates to a bicycle, in particular with a drive by an electric motor.

Bicycles with electric motors are known. You have a big one Battery on the luggage rack. The electric motor drives the tire via a drive wheel at. Switching this drive on and off is difficult.

The present invention is based on the object of a bicycle create that with low weight and high driving safety through great driving comfort and an electric one in every driving situation with simple means Drive can be switched on, which alone or in connection with the pedal drive the Bike drives and with easy switching on and off when driving uphill for charging the batteries are used.

To solve this problem, a bicycle with a drive proposed by an electric motor according to the invention that the electric drive and the pedal was driven to the gearbox via the associated chains and sprockets the rear hub act and the sprockets of both drive systems freewheels assigned. This proposal ensures that the pedal was driven individually and the electric drive can also act individually, but can also be connected to one another are, so that in addition to the pedal drive, the electric drive is effective.

This solution also ensures that, provided there is a type of drive predominates, an automatic decoupling from the other type of drive due to the freewheels he follows. As a result, there is no mechanical residual friction, especially when the pedal is operated of the electric drive available.

In a further embodiment of the invention it is proposed that the sprocket driven by the electric motor freewheels on the rear wheel hub and the sprocket driven by the pedal freewheels in the hub of the chainring Has. This solution ensures that there is sufficient space on the rear wheel hub is available to drive the aforementioned separation of pedal and electric drive or to effect a connection between the pedal drive and the electric drive.

In a further embodiment of the invention it is proposed that between the rear wheel hub sprocket driven by the electric motor and the There is a clutch at the rear wheel. This solution achieves that, for example when driving downhill, the electric motor to generate electricity to charge the batteries is used.

In a further embodiment according to the invention, there is the aforementioned Coupling made up of two pulley halves, one pulley on which is driven by the electric motor driven sprocket and the other disc on the rear edge, preferably the The hub of the rear wheel is attached and the pulleys are tensioned by a V-belts can be connected to one another. This solution is particularly simple and leaves attach to the hub to save space.

In a further embodiment of the invention it is proposed that the two pulleys are assigned a pulley for a V-belt and the Distance between the pulley and the pulleys is variable.

This is advantageously done by providing that the pulley is mounted on a lever around a to the axis of the pulleys and pulley located at a distance and parallel to it axis is pivotable.

Another proposal according to the invention is that the two Rear fork tubes can be swiveled around the axis of the pivot bearing housing as a fixed structural unit are mounted and at a distance from the pivot mounting the two rear fork tubes are connected to each other by a cross member to which the electric motor is attached is. This stipulation results in a particularly favorable arrangement of the electric motor, also with regard to the low center of gravity in the center of the bike. By this solution is also achieved that the chain of the electric drive and the Chain of the pedal drive through a common chain case absolutely dust-tight can be encapsulated without the need for special bellows, accordion seals, Length compensation slide or the like required would be because the chain case is in the bottom bracket axle can be firmly connected to this rear swing arm.

In a further embodiment of the invention it is proposed that the Structural unit of the rear fork tubes at their ends facing the bottom bracket Have bearing rings whose diameter is considerably larger than the outer diameter of the bottom bracket shell and in the gap between the bearings of the rear fork tubes and the outer surface of the bottom bracket shell bearings are inserted.

In a further embodiment of the invention it is proposed that the electric motor is provided with a spur gear, which is laterally over a rear wheel fork protrudes and with a larger diameter gear mounted on this rear fork that meshes with a sprocket for the chain drive of the sprocket on the rear wheel hub connected is.

This measure simplifies the arrangement of the transmission possible on one rear fork tube, which at the same time, as mentioned above, also through the chain case is sealed absolutely dust-tight.

Another suggestion according to the invention is the cross member to be designed as a tube and to arrange the electric motor in the tube. This results in a particularly simple and stable solution with effective protection of the electric motor.

In a further embodiment of the invention it is proposed that the space between the lower frame tube and the upper frame tube with a cladding is provided and in this cladding the batteries for driving the electric motor are arranged. So that the batteries are also in one with respect to the center of gravity favorable centric area of the bike.

In order to be simple and easy to adjust to the body weight of the user To achieve bicycle suspension is proposed in a further embodiment according to the invention, that a bracket is welded to the traverse to connect the two rear fork tubes is and a bracket is also welded to the seat tube and between the two Brackets as well as an exchangeable rubber block attached to them is available.

According to the body weight of the user or other wishes of the bicycle user is accordingly with the same dimensioning of the rubber block or the like material a desired one due to different Shore hardness Characteristic achieved. In order to use particularly simple rubber blocks of various To be able to exchange Shore hardness, is in a further embodiment according to the invention suggested that the two brackets from extending at a parallel distance from each other There are metal sheets, at the free ends of which ring disks are welded with a flanged edge and a large-diameter opening is provided eccentrically in the annular disks is, to which an opening in the center of smaller diameter is connected and the rubber block is provided with heads at both ends, the diameter of which slightly smaller than the diameter of the eccentric: openings in the ring discs and whose neck is slightly smaller in diameter than the central opening.

For the suspension of the front wheel, it is proposed that this be in the joint head tube is arranged. For this purpose, the solution that a in the steering head tube is particularly advantageous Guide tube is arranged, which in the upper area and in the lower area to two opposite sides has grooves for receiving balls and in the guide tube a fork tube is arranged in the same way as the guide tube in the upper Area and in the lower area of the grooves there for receiving the ball opposite Has grooves for receiving the aforementioned balls and inside the fork tube a spring element is arranged, which is located on a stop surface in the guide tube and a stop surface in the fork head. It is particularly advantageous the grooves for receiving the balls in the guide tube made of elongated, outwardly directed Characteristics and the grooves for receiving the aforementioned balls in the fork tube opposite, inward-facing characteristics.

In order to achieve particularly simple, safe guidance and, among other things, To compensate for manufacturing tolerances, is in a further embodiment according to the invention suggested that in the grooves of the guide tube with the interposition of rubber or similar rubber-elastic material designed as channels guide grooves are arranged in which in plant with the inwardly embossed grooves of the fork tubular balls, in particular a plurality of balls arranged one above the other are.

Although the electric bike with a variety of small batteries is provided to drive the electric motor, becomes an independent one in order to save electricity Power generation plant z. B. for lighting, proposed, this power generation system but also other functions can exercise so in conjunction with Electronic components for regulating an adjustable constant speed with the switching on and off of the electric motor to the pedal drive. These are Arranged on the rim of the wheel evenly spaced magnets and on the Magnet opposite side of the fork of the wheel one or more coils present.

The invention is illustrated by way of example in the drawings. Show it: 1 shows the bicycle as an electric bicycle in a side view; Fig. 2 after the bicycle Fig. 1 in a view from the front, Fig. 3 the drive of the rear wheel by pedal and / or electric motor in plan view, FIG. 4 shows the drive via pedal and drive via the electric motor according to the principle shown in Fig. 3 in side view, Fig. 5 shows the coupling between the engine-driven chain wheel on the rear wheel hub and the rear wheel according to FIG. 3 in side view, FIG. 6 the suspension of the front wheel in the longitudinal head tube in side view, Fig. 7 the suspension according to Fig. 6 ip a vertical Section according to the line VII-VII according to FIG. 6, FIG. 8 a FIG. 6 opposite modified solution, FIG. 9 shows a solution modified in relation to FIG. 7 in the vertical Section along the line IX-IX of FIG. 8, Fig. 10 the suspension of the rear wheel between the rear fork tube and seat tube in side view, Fig. 11 the mounting surface for the replaceable rubber block according to FIG. 10 in the view from above.

According to Fig. 1, the bicycle 10 has a pedal drive 11 with the chainring 12 and the chain 13 that drives the sprocket on the rear hub 14, like that will be described in detail with reference to FIG.

At 15, an electric motor is shown, which via a transmission Sprocket 16 drives, which drives sprocket 18 via chain 17.

Fig. 1 also shows that the suspension of the front wheel in the longitudinal head tube is arranged, as will be described in detail with reference to FIGS. 6 to 9 will.

Fig. 1 also shows that the aforementioned drives pedal and / or electric motors are covered dust-tight by a chain case.

There is also no conventional luggage rack, but behind the seat tube 20 is provided with a covering that merges into the mudguards, which has an upper end cover 21.

On the rim 22 of the front wheel there are magnets at regular intervals 23, 23a, 23b present, which are present in connection with one on the front fork 24 Coil 25 or more coils generate electrical current. This electricity generation by giving impulses can be done for the bicycle light 26 and that Taillight 27. The tachometer generator, which thus works without friction, can, as dependent pulses are given by the peripheral speed and the number of magnets, can also be used for other registration purposes, for example for determination the speed and the distance. The generated current pulses per unit of time but can also be used in conjunction with electronic switching elements are to maintain a certain speed in such a way that, provided that the User does not reach the speed via the pedal drive, automatically the Electric drive is switched on. The impulses can also lead to the Electric motor switched off or when driving uphill and exceeding a certain speed The electric motor generates electricity via a clutch to be described below and feeds the batteries in the area between the lower frame tube 28 and the upper Frame tube 29 are arranged.

This accommodation space for the batteries is provided with a covering 30.

The power generator consisting of magnets 23 and coils 25 is free from mechanical Friction. If a power consumer is switched on by a switch, is they effective.

The new generator made of magnets and coils is particularly suitable for the further proviso according to the invention that by scanning the vehicle speed, in particular through electronic pulse scanning, the motor only when it is reached a minimum speed of the bicycle, preferably about 1m per second will. This is to avoid using the electric drive to start up because most of the energy is needed to start up. But this should largely can be saved in order to increase the radius of action.

Incidentally, the batteries, which are individually 2 volts, are preferred 12 batteries switched for 24 volts, rechargeable, e.g. B.

by electricity of 220 volts. The charger can also and is advantageous in the space between the lower and upper frame tube in the area of the batteries.

2 shows the lamp body with flashing lights 31 in a top view and 32 and display instruments 33 and 34.

Fig. 3 shows a top view of the bottom bracket housing 35 with the pedal cranks 36 and 37 with pedal 38. With 39 the chainring is referred to, in which the freewheel of the pedal drive is available. From the chainring, the chain 40 goes out, which drives a sprocket 41 on the rear hub.

There is also another small sprocket 42, the Switching the chain 40 from one chain wheel 41 to the other chain wheel 42 or conversely takes place in a known manner.

The structural unit of the rear fork tubes 4T, 48 has on their to the Bottom bracket 35 facing ends of bearing rings 43, 44, the diameter of which is considerably larger is than the outer diameter of the bottom bracket shell 35 and into the gap between the bearing rings 43, 44 of the rear fork tubes and the outer surface of the bottom bracket shell 35 are bearings 45, 46 one is pushed. This allows the structural unit of the rear fork tubes Slide it over the bottom bracket shell with sufficient play, first of all on one side of the tubes 28, 20 and then, because tilting is possible, of the opposite side. The final attachment then takes place over the existing ones Caps 49 and 49a.

The two rear fork tubes 47 and 48 are in the vicinity of the bottom bracket housing 35 connected to one another by a cross member 50, which according to the exemplary embodiment is designed in the form of a tube and the rear fork tubes by welds 51 and 51a connects. In this tube, the electric motor 15 is arranged, the one to the outside from the fork tube 48 has protruding gear 53 which meshes with a gear 54, which is mounted in a bearing 55 on the fork tube 48. The electric motor as a direct current squirrel cage preferably has a power rating of 300 watts at 24 volts and 4500 revolutions per minute. Its speed is infinitely variable. It is controlled by one Voltage switch and electronic power regulator.

The spur gear 53 of the electric motor and spur gear 54 are in a reduction ratio from 1: 6 to 1: 7 available. On the spur gear 54, the sprocket 56 is present the drive chain 57 drives. This is guided around the sprocket 58, which is attached to the The driver of the drive is fixed in the hub. On the sprocket or ring gear 58 there is a pulley half 59, toothed cross 58 and pulley half 59 are preferably in one piece. Another pulley half 60 is present.

A V-belt 61 is provided between the two pulleys, the in the tensioned state, the two disks 59 and 60 are non-positively connected to one another. This can be seen in detail from FIG. It shows the disk in side view 60 and a deflection roller 62 arranged above the two disks 59 and 60, which is mounted on a fork 63. The fork 63 can be pivoted via a pin 64 mounted and on a projection 65 on the fork 48. The lever 63 is with a transverse surface 66 understand so in Connection with an adjusting screw 67 and a cable 67a removes the pulley 62 from the disks 59 and 60 and thus the V-belt 61 is tensioned and thus connects the two pulleys. Through this can, because now the rear wheel 68 via this disc clutch in connection with V-belt is connected to the sprocket 58, e.g. B. when going down a hill the chain 57 and the aforementioned gear 53 and 54 of the electric motor 15 generate electricity and charge the batteries. A return spring, not shown, is attached to the lever 63 present, so that the roller 62 approaches the pulleys and thus the V-belt 61 loosens and assumes its round shape. This will create the two discs separated again.

Fig. 6 shows in detail the solution to the arrangement of the suspension of the front wheel in the steering head tube 69, which is also shown in FIG. The steering head tube has on his both ends 70 and 71 bearing shells for receiving balls 72 and 73 for steering of the front wheel. Inside the steering head tube 69 there is a guide tube 74, that in the lower area on two opposite sides by embossing externally formed channel-shaped vertically directed grooves 75 and 76 for receiving Has balls 77 and 78 and is formed in the same way in its upper region Grooves 79 and 80 obtained by embossing for receiving balls 81 and 82.

This guide tube 74, also shown in FIG. 7, consists of two parts or shells 74a and 74b and is divided in the longitudinal direction.

This division is indicated by the dividing lines 74c and 74d. These The division runs transversely to the grooves 79 and 80 obtained by the embossing.

This is necessary in order to be able to arrange the balls. Within the Guide tube 74, the fork tube 83 is available, which is not divided into two parts. It has inwardly directed grooves 84 in its lower area due to embossments and 85 for the aforementioned balls 78 and 77 as well as in its upper region in the same way Ball guide grooves 86 and 87 obtained in this way. The assembly is carried out in the following way: Grease is introduced into the guide grooves of the fork tube. Then be into this the balls inserted. Then the two shell halves of the guide tube 74 joined together, as can be seen from FIG. The two shell halves of the guide tube are surrounded in the lower area by a bearing ring or a bearing shell 88, which inserted from above, on a circumferential projection 89 of the guide tube 74 supports. The bearing shell 88 has recesses on the inside on two opposite sides, so that they have the outwardly directed expressions 75, 76 for the ball races the guide tube can be pushed.

Within the fork tube 83 is a spring 90 in the form of a helical spring arranged, which strikes at the top of a stop 90a and at the lower end of a Stop surface in the fork head.

Fig. 6 shows the position downwards, i.e. H. lowered fork tube.

When the spring deflects, the fork tube moves upwards, the stroke path twice as long as a groove, for example 86, because the grooves act as guides of the balls of the fork tube and guide tube add up.

FIG. 8 shows an improved solution in FIG. 6 opposite Way that in the grooves of the guide tube 74 by interposition from Rubber or similar rubber-elastic material 91 formed as grooves 92 Guide grooves for a plurality of balls 81, 81a arranged one above the other are arranged. The balls 81,81a engage in the vertical manner in the manner described for FIG. 6 by embossing inwardly obtained groove of the fork tube 81 a. In the representation According to FIG. 9, the guide tube is also in a plane transverse to the plane of the guide grooves separate for the balls and thus consisting of two shells. The arrangement of the Grooves 92 are attached to the guide tube 74 with the interposition of rubber or silent rubber, here, preferably vulcanized, has the advantage that it is considerably gentle on the material the balls and raceways takes place because no hard vibrations are transmitted will. By determining the thickness and Shore hardness of the silent rubber 91 are the properties of the suspension can also be changed. Another key consideration is that now in series production not manufactured with very precise tolerances must be because the silent rubber a uniform contact of the balls on the associated There are running surfaces in the guide grooves.

The silent rubber thus compensates for tolerances. He leads to one low preload and thus good contact of the balls on their running surfaces in the Grooves. Also, the balls cannot slip away that much.

The arrangement of the silent rubber also has the advantage that no career and road noise are transmitted.

Fig. 10 shows that on the cross tube 49, which also the electric motor 15 receives, two sheets 93 and located at a lateral distance from one another 94 are present, which are provided with an annular disk 95 which has a flanged Edge 96 has.

In the same way, two metal sheets 97 are welded to the seat tube 20, which also v) rnz have an annular disk 98, which is in the same way as the annular disk 95 is formed. The ring disks each have an eccentric opening 98 larger diameter and a central opening 99 of smaller diameter for Receiving a rubber block 100, which has a head 101 at both ends has a neck 102.

This rubber block 100 of cylindrical design is preferably at of the same length in different Shore hardnesses, thus depending on the weight of the Driver or other conditions without tools a replacement and thus a other suspension characteristics can be obtained. To a rubber block 100 against To exchange another one, the bike is lifted by the saddle, for example. As a result, the two ring disks 95 and 98 move apart somewhat. The rubber block is then moved so that the heads 101 out of the large opening 98 can be removed. When inserting another rubber block the heads 101 are inserted into the large bore 98. Then the Block shifted so that the thinner neck is correspondingly smaller in the recess 99 Diameter is centered. Blank page

Claims (22)

Claims g bicycle with a drive by an electric motor, it is indicated that the electric drive (15) and the pedal drive (36,37) via assigned chains (57,40) and chain wheels (58,41) act on the gear of the rear wheel hub (9) and the sprockets (58,41) of both Drive systems are assigned freewheels. 2. Bicycle according to claim 1, d a d u r c h g e k e n n -m e i c h n e t that the chain wheel (58) driven by the electric motor (15) is freewheeling on the rear wheel hub (9) and the chain wheel (41) driven by the pedal (36937) Has freewheel in the hub of the chainring (39). 3 bicycle according to claims 1 and 2, d a d u r c h g e -k e n n z e i c h n e t that the pedal drive on the rear hub is known per se Way has two or more sprockets (41,42). 4 bicycle according to claim 1, d u r c h g e k e n n -z e i c h n e t that by a driving speed scan, in particular by an electronic Pulse scanning of the motor (15) only when a minimum speed of the is reached Bicycle, preferably about one meter per second, is turned on. 5. Bicycle according to claims 1 to 4, d a d u r c h gek e n n z ei c h ne t that between the chain wheel (58) driven by the electric motor (15) the rear wheel hub and the rear wheel (68) have a coupling (59, 60, 61). 6. Bicycle according to claim 5, d a d u r c h g e k e n n -z e i c h n e t that the coupling consists of two pulley halves (59,60), one Washer (59) on the sprocket (58) and the other washer (60) on the rear wheel, preferably the hub (68a) of the rear wheel is fastened via bolts (68b) and the pulleys (59, 60) with one another by means of a tensioned V-belt (61) are connectable. 7. Bicycle according to claim 6, since you r c h gek e n n -z e i c h n e t that the two pulleys (59, 60) have a pulley (62) for a V-belt (61) and the distance between the pulley (62) and the pulleys (58,59) is changeable. 8. Bicycle according to claim 7, d a d u r c h g e k e n n -z e i c h n e t that the pulley (62) is mounted on a lever (63) which is around a to The axis of the pulleys and idler pulley are spaced and parallel to them extending axis (64) is pivotable. 9. Bicycle according to claim 1 and one or more of claims 2 to 8, d u r c h e k e n n n z e i c h n e t that the two rear fork tubes (47, 48) can be pivoted as a structural unit around the axis of the bottom bracket housing (35) are stored and the two rear fork tubes at a distance from the pivot bearing (47,48) are connected to one another by a cross member (50). 10 bicycle according to claim 8, d u r c h g e k e n n -z e i c h n e t that the electric motor (15) is arranged on the cross member (50). 11. Bicycle according to claim 9, d a d u r c h g e k e n n -z to e i c h n e t that the structural unit of the rear fork tubes (47,48) at their to the Bottom bracket (35) facing ends have bearing rings (43, 44), the diameter of which is considerable is larger than the outer diameter of the bottom bracket housing (35) and into the gap between the bearing rings (43,44) of the rear fork tubes and the outer surface of the bottom bracket shell Bearings (45, 46) are inserted. 12. Bicycle according to claim 9, d a d u r c h g e k e n n -z e i c h n e t that the electric motor (15) is provided with a spur gear (53) which is laterally protrudes beyond a rear fork (48) and with one on this rear fork stored Gear (54) meshes with a larger diameter Chain wheel (56) for the chain drive of the chain wheel (41) on the rear wheel hub (9) connected is. 13. Bicycle according to claim 10, d a d u r c h gek e n n -z e i c h n e t that the cross member is designed as a tube (50) that the electric motor (15) records. 14. Bicycle according to claim 1 and one or more of the claims 2 to 13, characterized in that the space between the lower frame tube (28) and the upper frame tube (29) is provided with a lining (30) and in this Cladding the batteries for driving the electric motor (15) are arranged. 15. Bicycle, in particular according to claim 1 and one or more of claims 2 to 14, since you r c h gek e n n -z e i c h n e t that on the traverse A bracket (93, 94) is welded on (50) to connect the two rear fork tubes (47, 48) is and a bracket (97) is also welded to the seat tube (20) and a replaceable rubber is attached between the two brackets and on them block (100) is present. 16. Bicycle according to claim 15, d a d u r c h g e ke n n -z e i c h n e t that the two brackets (93,97) from at a parallel distance from one another extending sheets exist, at the free ends of which washers (95,98) with flanged , Edge (96) are welded and an opening (98) off-center in the ring disks large diameter is available, to which there is an opening in the center (99) with a smaller diameter and the rubber block at both ends is provided with heads (101), the diameter of which is slightly smaller than the diameter of the eccentric openings (98) in the annular disks and their neck (102) in the Diameter is slightly smaller than the central opening (99). 17. Bicycle, according to in particular claim 1 and one or more of claims 2 to 16, d a d u r c h gek e n n -z e i c h n e t that the suspension of the front wheel or the front fork is arranged in the steering head tube (70). 18. Bicycle according to claim 17, d a d u r c h gek e n n -z e i c h n e t that a guide tube (74) is arranged in the steering head tube (70), which in the upper Area and in the lower area on two opposite sides grooves (79,80) (75,76) for receiving balls (81,82,77,78) and a fork in the guide tube (74) tube (83) is arrangedx that in the same way as that Guide tube in the upper area and in the lower area the grooves there for receiving the ball opposing grooves (84,85,86,87) for receiving the aforementioned balls (77,78,81,82) having and inside the fork tube a spring element (90) is arranged which on a stop surface (90a) in the guide tube (83) and a stop surface (90b) is supported in the fork head (91). 19. Bicycle according to claim 16, d a d u r c h g e ke n n -z ei c h ne t that the grooves for receiving the balls in the guide tube are elongated towards the outside directed expressions (75,76,79,80) and the grooves for receiving the aforementioned Balls in the fork tube from opposite, inwardly directed forms (84,85,86,87) exist. 20. Bicycle according to claim 19, d a d u r c h g e ke n n -z e i c h n e t that in the grooves of the guide tube with the interposition of rubber (91) or similar rubber-elastic material as channels (92) formed guide grooves are arranged in which in contact with the inwardly embossed grooves of the fork tubular balls, in particular a plurality of balls (81) lying one above the other are. 21. Bicycle according to claims 18 to 20, d a d u r c h gek e n n z ei c h ne t that the guide tube (74) in its longitudinal direction is divided and this division by 900 to the grooves (79,80) for receiving the balls is offset and the two shells (74a, 74b) at the lower end of a bearing shell (88) of the lower steering head tube is surrounded, which holds the guide tube (74) together and pins are present transversely to the parting plane, which allow an axial displacement of the two Prevent guide rail halves (74a, 74b), furthermore the aforementioned lower Bearing shell (88) has two recesses on its inside so that it can be covered Push the protruding protrusions (75,76,79,80) of the ball raceways leaves. 22. Bicycle, in particular according to claim 1 and one or more of claims 2 to 17, d a d u r c h gek e n n -z ei c h ne t that on the circumference of the Rim (22) of the wheel, in particular the front wheel, magnets at an even distance (23,23a etc.) are arranged and on the opposite side of the magnet (23) the fork (24) of the wheel a coil (25) or several coils (25) are arranged.